… The company’s marketing executives determined their paid ads had little impact on consumers, people familiar with the matter said, a move that comes as more companies question the effectiveness of advertising on the social networking site.

The largest U.S. auto maker will continue to expand its use of marketing through Facebook’s pages, in which markers can display content at no cost, these people said.

The move comes just days before Facebook’s much-publicized stock offering, Forbes.com said.

GM spends about $40 million a year on Facebook marketing, according to the Wall Street Journal, about $10 million of which is for paid advertisements. It will continue to post relevant content about the company and its brands on GM’s Facebook pages.